On the human colony on the planet Pluto citizen Cordo hears of his father's death but when he goes to pay the death taxes he finds he hasn't enough money. In despair he goes to throw himself off a tower block but is prevented from doing so by the arrival of the Doctor & Leela. He tells them how the company runs the planet, are responsible for the artificial suns and tax the population to death. The Tardis is detected and the Gatherer investigates with the Doctor, Leela & Cordo fleeing to the under city, where Cordo goes to join a group of outlaws. They are captured and taken to the group's leader Mandrel. K-9 exits the Tardis and is detected by the Gatherer. The Doctor is sent to use a stolen Consumcard, with the threat that if he's not back within a certain time they will kill Leela. K-9 finds the Doctor & Cordo but the stolen Consumcard is detected and the Doctor is gassed.

Ah now that's just fabulous, really is. For a episode that opens with someone's father dying, moves into despair at not affording taxes and gets to an attempted suicide then followed up by a bit of cashpoint fraud, it rolls along at a nice pace and is bright and funny. Of particular note is Richard Leech's fabulous performance as the Gatherer. As he & Marn find the Tardis and speculate on why it's here it forms a perverse commentary to the story. I'm reminded somewhat of Paul Whitsun-Jones in the Mutants. There the character was nasty and malicious, here it works.

I saw the cash machine at the end of this episode and thought "isn't 1977 a little early for cash machines?" A little research reveals the first one was used in the UK in 1967!

A couple of notes on the end credits: firstly there's no script editor credited because Robert Holmes is the writer of this story. I also see a first visual effects credit for Peter Logan who I believe to be the same Peter Logan who appears with his exploding paste on Braniac Science Abuse

As we previously said the production order for this season was vastly different from the transmission order. Sunmakers was recorded third, after Horror of Fang Rock (broadcast first) and before Image of the Fendahl (broadcast third, before this story). Apparently Sunmakers was due to be broadcast third but someone realised that meant there were two "humans in space" stories on the trot so it was swapped with Image of the Fendahl.

It's quite possible that my earliest memory of Doctor Who, of the Doctor meeting K-9 in a tunnel, comes from this episode.